1. Field of the Invention
The invention relates to building materials and products, and, more particularly, to a vertical, water-based application on an insulation board assembly having non-cellulosic facers thereon.
2. Background of the Invention
Rigid polymeric foam insulation laminates have been used for many years by the construction industry. Uses include commercial roof insulation boards utilized under asphaltic built-up roof (BUR) membranes as well as under various single ply membranes such as EPDM rubber, PVC, modified bitumen membranes and the like. Other uses include residential insulation, as sheathing under siding, and as roof insulation under asphalt shingles and concrete tiles.
Such insulation often takes the form of a core polymeric foamed thermoset material such as polyurethane, polyisocyanurate, polyurethane modified polyisocyanurate (often referred to as polyiso) or phenolic resin, applied between two facing sheets.
The insulation boards are generally manufactured on production lines where a liquid core chemical mixture is poured over a bottom facer, foaming up to contact a top facer in a constrained rise laminator. The reaction of the chemical mixture causing foaming is generally exothermic, as curing via polymerization and crosslinking occurs in the laminator. In the case of polyisocyanurate insulation boards, the curing exotherm lasts well into the time the resulting rigid boards are cut, stacked and warehoused. The exotherm can continue for as long as 4 days and the mixture can reach temperatures as high as 325° F.
Desirable properties for the facers include water resistance or waterproof, flexibility, high tensile and tear strength as well as resistance to thermal degradation. The facer should prevent bleed-through of the liquid chemicals from the board prior to foaming. Additionally, facers should exhibit good adhesion to the core foam insulation and be inert to the effects of extraneous chemicals that may be present in the mixture, especially blowing agents that may also behave as solvents.
Traditionally, facer materials have included cellulose, asphalt saturated cellulosic felts, fiberglass mats, asphalt emulsion coated fiberglass mats, aluminum foil/Kraft/foil, glass fiber modified cellulosic felts, glass mats onto which polymeric films have been extruded, and glass mats coated with polymeric latex/inorganic binder coatings. However, all of these materials have undesirable properties. For example, cellulose facers degrade when exposed to water or water based cementious material. Asphalt-containing products are not compatible with PVC single ply roofing membranes. Fiberglass mats are subject to excessive bleed-through of foamable core chemicals. Aluminum facers and foils reflect heat into the foam during processing which leads to disruption of cell structure, delamination and warping. Further, foil faced sheathing and extrusion or lamination of a polymer film to glass mat surfaces are costly. Specifically, glass mats coated with polymer latex/inorganic binder mixtures have been found to be brittle; conversely, glass fiber modified cellulosic felts are susceptible to moisture absorption aggravating board warping in damp or wet environments.
For vertical building materials, expanded polystyrene (“EPS”) board is commonly used as a sheathing. EPS is water resistant allowing for water based applications to be applied. However, EPS also has many deficiencies. EPS flows when heated, offers less insulation (has a lower “r” value) than polyiso, and is relatively fragile.
Polyiso is more tough and provides better insulation than EPS. However, polyiso with a paper facer is incompatible with water based applications since the paper expands and degrades when exposed to water.
The prior art boards and facers would all suffer from various problems as they relate to water-based cementatious vertical overlayments. Therefore, plywood and building paper has most often been used for such applications. As shown in FIG. 1, the prior art building product for water based vertical applications comprises a plywood undersiding board 2 fixed to a wood frame 4. A building paper 6 is applied over the undersiding that is typically an asphalt-saturated paper felt. A metal reinforcement or lath 8 is then typically installed by nail or staple to the structure. This metal mesh supports the cement plaster application 10 that may be applied to it in several layers. Acrylic finishes 12 may also be applied to such a vertical application. The prior art is undesirable since these materials are not water resistant or good insulators.